We've done 14, from Cedar City to 89. We traveled it in late October, leaving Cedar City in rain, and hitting snow 1/2 way to the summit. There are signs saying "No Tractor-Trailers", but I don't remember if they were on the edge of town, or farther up the road. Overall, it's a decent road, with 2 or 3 tight corners. Drive aware, watch your speed, and watch your mirrors. We never crossed the centre line, except one corner that had snow built up on the shoulder, and it was more prudent to use the clear road.
Edit to add: I just drove the road, using Google Maps. The signs are a couple miles out of town, past the sign advising of 8% grades ahead. The wording on the signs is actually "Not Recommended for Semi Trucks", so it's up to you. I do remember using stage 2 and 3 in 8th gear going down after the summit.